Abstract:The purpose of this research was to establish a suitable two-dimensional electrophoresis system by optimizing the parameters including the different IPG strips,isoelectric focusing conditions,different gel concentrations and sample loading for intercellular washing fluid of cucumber leaves to analyze proteomics.Cucumber seedling leaves of the variety PI088 was used in the experiment,extracting the intercellular washing fluid and preparing for protein samples.(1)As shown by the results,with pH 3~10 nonlinear IPG strips,under the conditions of isoelectric focusing 70 000 Vh,10% separating gel concentration,sample volume 800 μg,we got a clear two-dimensional electrophoresis map.(2)The proteomics profiling of intercellular washing fluid of cucumber leaves in different inoculation time was analyzed by using the previous established protocol.We found 12 up-regulated and 10 down-regulated proteins with more than 1.5 times changes in 2 days after inoculating with Pseudoperonospora cubensis compared with control and one of the different protein spots were successfully identified.(3)Mass analysis showed that the different point is an acidic chitinase and the isoelectric point is 4.27.Reproducible profiles with high resolution were obtained by this 2-DE system.